A large operator of a brown field offshore in the middle east has decided to provide full lower Completionaccessibility and ensure prevention of open hole collapse as it can lead to various gains throughout the lifeof the well.Among those benefits,it provides a consolidated well bore for various production logging &stimulation tools to be deployed effectively,as well as full accessibility,conformance control and enable toprovide production allocations for each zones.However there are multiple challenges in deploying lowercompletion liner in drains involving multiple reservoirs and geo steered wells:Well Bore Geometry,doglegs/tortuosity etc.& differential sticking possibilities and of course the open hole friction.Due to the sizeof the open hole,restricted casing design and utilization of limited OD pipes further add to the complicationsof deploying the Lower completion liner in such brown Field wells.This paper intend to review the multi-step methodology approach implemented in recent years by thecompany to effectively deploy 4-1/2″ Liner in 6″ Horizontal Open Hole section.Among the techniques usedto assist successful deployment of lower completions are:Improving hole cleaning,ensure smooth wellbore with the use of directional drilling BHA,reduction of the Open Hole friction by utilizing Lubricatedbrines,fit for purpose Centralizers,use of drill pipe swivel devices to increase weight available to push theliner & reduce buckling tendency.With the length of open hole laterals reaching up to 10,000 ft for 6″ Lower drains,open hole drag,friction & cleanliness are major components that causes challenges in deploying the Liner till TD.Theuse of specially formulated brines with fixed percentage of lubricants proved to significant reduce frictioncompared to the drilling mud used for drilling the horizontal drain.The combination of low friction brinewith proper centralization/standoff which resulted in reduced contact area with the formation has alsoshown good results in preventing differentials sticking while running the liner through multilayer reservoirshaving significantly different reservoir pressures.Another major constrain to deploy the lower completion liner in this offshore field is the very nature ofthe wells being primarily workover.This involves generally Tie back liners run to shallow depths to restorethe integrity of wells.This limits our ability in the selection of drill pipe that can be used as only smallerOD drill pipes and HWDP can be utilized in order to deploy the Liner to bottom.On many occasions thisprovides only limited weight to push the Liner down to TD and impact our ability to set the liner top packer.Drill pipe rotating swivel devices have been utilized to improve our weight availability & transferability topush the liner down and to set the liner top packers.In order to provide independent deactivation mechanismfor the drill pipe swivel and to have complete success in our liner deployments,a dedicated ball activatedsub was designed to deactivate the swivel acting as back up in case primary deactivation methods failsduring liner setting.The combined use of all these techniques enabled the company to deploy 4.5″ Liners in 6″ Horizontaldrains with high success in this offshore Brown Oil field of UAE.This resulted in better well constructionand complete access to lower drains over the life of the wells.
展开▼
